中文摘要：

目的 研究体外培养条件下银杏叶提取物（ginkgo biloba leaf extracts．EGb）对三氯乙烯（trichioroethvlene，TCE）诱导的正常人表皮角质形成细胞（normal human epidernis keratinocyte，NHEK）凋亡的影响。方法体外培养条件下，用中性红吸附试验（NRU）测定TCE对NHEK的中性红吸附减少50％的质量浓度（NR50值）和EGb的最低有效保护质量浓度。用透射电子显微镜（transmission electron microscope，TEM）观察细胞凋亡形态学改变，流式细胞仪（flow cytometer，FCM）测定细胞DNA含量并计算凋亡发生率。结果 TCE对NHEK的NR50值为4．53（3．92～5．13）mmol／L；用10、50、100、150和200mg／LEGb预孵育NHEK2h时，由2．0mmol／L TCE引起的细胞活力的下降随EGb剂量的增加逐渐恢复，且150mg／L为最低有效保护剂量。TCE可引起NHEK的超微结构呈凋亡改变，凋亡发生率呈剂量依赖式增加。与0．125、0．5和2.0mmol／L TCE暴露组相比，150mg／L EGb预孵育组，细胞超微结构恢复到正常对照组水平，凋亡发生率明显减少。结论 体外培养条件下，EGb可以抑制TCE诱导的NHEK的细胞凋亡。

英文摘要：

Objective To study the effects of ginkgo biloba leave extracts （EGb） on trichloroethylene （TCE）-induced apoptosis in normal human epidermal keratinocytes （NHEK） in vitro, Methods NR50 values of TCE to NHEK and the lowest effective protection dose of EGb were assayed by neutral red uptake （NRU） in vitro. Transmission electron microscope were used to observe morphologic changes, flow cytometer was used to measure DNA contents and calculate cell apoptosis rate. Results NR50 values of TCE on NHEK was found to be 4.53 mmol/L（CI 95% ： 3.92-5.13）. Pre-treatment of EGb at 10,50,100,150,200 mg/L for 2 h, dose-dependently attenuated the cytotoxic effect of 2.0 mmol/L TCE, the lowest effective protection dose of EGb were 150 mg/L . TCE could cause typical morphologic changes of apoptosis and apoptotic rate increase in dose-dependently. Compared with 0. 125, 0.5, 2.0 mmol/L TCE exposure group, cell were preincubated with 150 mg/L EGb prior to TCE were restored normal control in morphologic changes and decreased meaningful in apoptosis rate. Conclusion These results suggest that EGb can obviously inhibit NHEK from TCE-induced apoptosis in vitro.